To know something by heart is to be confident that you have memorized the technicalities of a thing… whether it is the lyrics to a song, the words to a script, the rules of the road, the words to a prayer, etc.

If I know a song by heart, then I can trust my ego to get out of the way and let authentic soulfulness be expressed, through my instrument, which is my whole body. Sometimes I accompany myself with a guitar.

If I know a prayer by heart, then I can let my thinking fall away and let authentic soulfulness be expressed by my openness to what is Real.